Two-component coating composition and method of preparation

ABSTRACT

Aqueous coating compositions containing (1) a first polymer containing reactive functional groups with a selected level of carboxylic acid functionality and (2) a polyfunctional crosslinker agent containing functional groups that are reactive with appropriate functional groups of the first polymer, are disclosed. The two-component polymer compositions provide a combination of durability and ready removability of the final coating after curing. Two-component polymer compositions based on the first polymer containing hydroxyl functionality in addition to carboxylic acid functionality and use of a polyisocyanate as the polyfunctional crosslinker agent are especially useful as floor polish compositions.

BACKGROUND

[0001] The present invention relates to the use of aqueous-based polymercompositions containing a first component bearing reactive functionalgroups that are post-reacted with other functional groups in a secondcomponent to promote crosslinking during application of the aqueouscomposition to a substrate to form a protective film. Formulatedcompositions of the present invention are particularly useful in polishand coating compositions where the combination of detergent resistanceand removability are desirable.

[0002] Conventional polish and coating applications, where durabilityand toughness are important, use polymers involving metal ioncrosslinking agents. For example, the use of mixed (divalent/monovalent)metal ion crosslinked polymers has provided a dramatic improvement ingloss and durability properties compared to conventional zinc ion(divalent) crosslinking chemistry.

[0003] U.S. Pat. Nos. 5,252,696, 5,468,804 and 5,670,600 disclose theuse of polyisocyanates as one binder component in two-component coatingcompositions where the second binder components (containing hydroxylgroups) have number average molecular weights up to 50,000.

[0004] U.S. Pat. No. 4,622,360 discloses the preparation ofsingle-component coating compositions where a polyurethane modified withcarboxyl groups is crosslinked with a polyvalent metal ion beforeapplication of the coating to a substrate. EP 367,812 discloses thepreparation of single-component coating compositions where apolyacrylate is polymerized in the presence of a polyisocyanate toprovide crosslinking before application of the coating to a substrate.

[0005] Current, non-metal crosslinked, single-component aqueous basedpolymers are known to be sensitive to scratching and pad swirling frombuffing and burnishing pads used to maintain the polish coating duringfloor maintenance procedures. The pad scratching phenomenon is believedto be due to poor film toughness. The problem addressed by the presentinvention is to provide a process for formulating a coating composition,particularly floor polish, that is highly durable to wear and resistantto washing with detergents, but is readily removable with stripper.

STATEMENT OF INVENTION

[0006] The present invention provides a method for preparing a coatingcomposition comprising (A) forming an aqueous-based mixture by combining(i) a first polymer comprising, as polymerized monomer units: (a) 5 to50 percent, based on weight of the first polymer, of a monoethylenicallyunsaturated monomer containing an acidic functional group selected fromone or more of carboxylic, sulfonic and phosphonic groups; (b) zero upto 60 percent, based on weight of the first polymer, of a (meth)acrylicmonomer containing one or more pendant reactive functional groupsselected from hydroxy, thiol, and amino groups; (c) zero up to 70percent, based on weight of the first polymer, of one or morevinylaromatic monomers; (d) 15 to 90 percent, based on weight of thefirst polymer, of one or more (C₁-C₂₀)alkyl (meth)acrylate estermonomers; and (e) zero up to 10 percent, based on weight of the firstpolymer, of one or more other copolymerizable monomers; and (ii) apolyfunctional crosslinker agent comprising pendant functional groupsselected from one or more of isocyanate, carbodiimide, aziridinyl andepoxy groups; wherein, the first polymer has a number average molecularweight from greater than 50,000 up to 2,000,000; and the polyfunctionalcrosslinker agent is used in an amount sufficient to provide from 0.2 to5 equivalents of pendant functional group per equivalent ofcorresponding pendant reactive functional group in the first polymer;and (B) applying the aqueous-based mixture to a substrate.

[0007] In a preferred embodiment, the present invention provides amethod for preparing a coating composition comprising: (A) forming anaqueous-based mixture by combining (i) a first polymer comprising, aspolymerized monomer units: (a) 16 to 20 percent, based on weight of thefirst polymer, of monoethylenically unsaturated monomer containing acarboxylic acid functional group; (b) 3 to 15 percent, based on weightof the first polymer, of a (meth)acrylic monomer containing hydroxyfunctional groups; (c) 20 to 50 percent, based on weight of the firstpolymer, of vinylaromatic monomer; and (d) 25 to 45 percent, based onweight of the first polymer, of one or more (C₁-C₈)alkyl (meth)acrylateester monomers; and (ii) a polyfunctional crosslinker agent comprisingisocyanate pendant functional groups; wherein, the first polymer has anumber average molecular weight from 200,000 to 1,000,000; and thepolyfunctional crosslinker agent is used in an amount sufficient toprovide from 0.2 to 5 equivalents of pendant functional group perequivalent of corresponding pendant reactive functional group in thefirst polymer; and (B) applying the aqueous-based mixture to asubstrate.

[0008] The present invention further provides an aqueous coatingcomposition comprising: (1) a first polymer comprising, as polymerizedmonomer units: (a) 5 to 50 percent, based on weight of the firstpolymer, of a monoethylenically unsaturated monomer containing an acidicfunctional group selected from one or more of carboxylic, sulfonic andphosphonic groups; and (b) zero up to 60 percent, based on weight of thefirst polymer, of a (meth)acrylic monomer containing one or more pendantreactive functional groups selected from hydroxy, thiol, and aminogroups; and (c) zero up to 70 percent, based on weight of the firstpolymer, of one or more vinylaromatic monomers; and (d) 15 to 90percent, based on weight of the first polymer, of one or more(C₁-C₂₀)alkyl (meth)acrylate ester monomers; and (e) zero up to 10percent, based on weight of the first polymer, of one or more othercopolymerizable monomers; (2) a polyfunctional crosslinker agentcomprising pendant functional groups selected from one or more ofisocyanate, carbodiimide, aziridinyl and epoxy groups; (3) 0.1 to 15percent, based on weight of the aqueous coating composition, ofcoalescing agent; (4) zero up to 10 percent, based on weight of theaqueous coating composition, of additives selected from one or more ofwaxes, surfactants, defoamers, leveling agents, alkali-soluble resinsand plasticizers; and (5) 50 to 99 percent, based on weight of theaqueous coating composition, of water; wherein: the first polymer has anumber average molecular weight from greater than 50,000 up to2,000,000; the polyfunctional crosslinker agent is used in an amountsufficient to provide from 0.2 to 5 equivalents of pendant functionalgroup per equivalent of corresponding pendant reactive functional groupin the first polymer; the combined amount of (1) and (2) is from 10 to90 percent, based on weight of the aqueous coating composition; and thesum of (1), (2), (3), (4) and (5) percents add up to 100 percent.

DETAILED DESCRIPTION

[0009] We have discovered that protective coatings having enhanceddurability (such as detergent resistance), yet also having easyremovability (such as during stripping operations), can be prepared fromtwo-component polymer compositions based on using (1) a first polymercontaining reactive functional groups with a selected level ofcarboxylic acid functionality and (2) post-crosslinking with apolyfunctional crosslinker agent containing functional groups that arereactive with the appropriate functional groups of the first polymer.The selected level of acid functionality in the first polymerunexpectedly provides the combination of durability and readyremovability of the final coating after curing. The two-componentpolymer compositions of the present invention provide the easyremovability characteristics of conventional single-component metal ioncrosslinked floor polish compositions with the added benefit of enhanceddurability, which the conventional floor polish compositions lack.

[0010] As used herein, the following terms have the designateddefinitions, unless the context clearly indicates otherwise. The term“alkyl (meth)acrylate” refers to either the corresponding acrylate ormethacrylate ester; similarly, the term “(meth)acrylic” refers to eitheracrylic or methacrylic acid and the corresponding derivatives, such asesters or amides. All percentages referred to will be expressed inweight percent (%), based on total weight of polymer or compositioninvolved, unless specified otherwise. The term “copolymer” refers topolymer compositions containing units of two or more different monomers.The following abbreviations are used herein: g=grams, L=liters,ml=milliliters, mm=millimeters, cm=centimeters, rpm=revolutions perminute. Unless otherwise specified, ranges listed are to be read asinclusive and combinable and temperatures are in degrees centigrade (°C).

[0011] For the purposes of the present invention, the first component orFirst polymer (containing selected levels of carboxylic acid monomerunits and optional other functional groups) will be referred to aspolymer A and the second component, containing pendant functional groupsreactive with selected functional groups of the first polymer (polymerA), will be referred to as polyfunctional crosslinker agent, and mayalso be referred to as polymer B when the polyfunctional crosslinkeragent is based on a polymeric material. Protective coatings producedfrom the curing of the two-component polymer compositions of the presentinvention or produced from the curing of other polymer compositions(such as one-component polymer compositions) for comparative purposes,will be referred to as “polish films.”

[0012] The polymers used as polymer A of the present invention contain,as polymerized units, from 5 to 50%, preferably from 9 to 40%, morepreferably from greater than 15 up to 30% and most preferably from 16 to20%, of one or more monoethylenically unsaturated monomers containing anacidic functional group selected from one or more of carboxylic,sulfonic and phosphonic groups. Suitable carboxylic acid monomersinclude monoethylenically unsaturated (C₃-C₉)carboxylic acid monomers,such as unsaturated monocarboxylic and dicarboxylic acid monomers. Forexample, unsaturated monocarboxylic acids include acrylic acid (AA),methacrylic acid (MAA), α-ethacrylic acid, β, β-dimethylacrylic acid,vinylacetic acid, allylacetic acid, ethylidineacetic acid,propylidineacetic acid, crotonic acid, acryloxypropionic acid and alkaliand metal salts thereof. Suitable unsaturated dicarboxylic acid monomersinclude, for example, maleic acid, maleic anhydride, fumaric acid,itaconic acid, citraconic acid, mesaconic acid, methylenemalonic acidand alkali and metal salts thereof Other suitable acidicmonoethylenically unsaturated monomers include the partial esters ofunsaturated aliphatic dicarboxylic acids (alkyl half esters); forexample, the alkyl half esters of itaconic acid, fumaric acid and maleicacid wherein the alkyl group contains 1 to 6 carbon atoms (methyl aciditaconate, butyl acid itaconate, ethyl acid fumarate, butyl acidfumarate and methyl acid maleate). Preferably, the monoethylenicallyunsaturated (C₃-C₉)carboxylic acid monomers are selected from one ormore of acrylic acid and methacrylic acid. Additional monoethylenicallyunsaturated monomers containing sulfonic acid or phosphonic groupsinclude, for example, 2-acrylamido-2-methyl-1-propane-sulfonic acid,2-methacrylamido-2-methyl-1-propanesulfonic acid,3-methacryl-amido-2-hydroxypropanesulfonic acid, allylsulfonic acid,methallylsulfonic acid, allyloxybenzenesulfonic acid,methallyloxybenzenesulfonic acid,2-hydroxy-3-(2-propenyloxy)propanesulfonic acid,2-methyl-2-propene-1-sulfonic acid, styrene-sulfonic acid, vinylsulfonicacid, 2-sulphoethyl methacrylate, 3-sulfopropyl acrylate, 3-sulfopropylmethacrylate, sulfomethyl acrylamide, sulfomethyl methacrylamide andphosphoethyl methacrylate.

[0013] The acid functionality level of polymer A controls the ease ofremovability of dried films (for example, a polish film) based on usingthe post-crosslinked polymer compositions of the present invention. Acidlevels of greater than 15% up to 25% are particularly preferred toenhance film removal and ease of film removal properties of thetwo-component coating compositions of the present invention in floortest evaluations. The use of excess acid functionality (greater than50%) in polymer A is detrimental to aqueous solution resistance andscrubbing resistance (alkaline detergent solutions) of the polish film.

[0014] The polymers used as polymer A of the present invention mayoptionally contain, as polymerized units, from zero up to 60%,preferably from 1 to 50%, more preferably from 2 to 40% and mostpreferably from 5 to 20% of a (meth)acrylic monomer containing one ormore pendant reactive functional groups selected from hydroxy, thiol,and amino groups. Suitable hydroxy-functional (meth)acrylic monomersinclude, for example, hydroxy(C₁-C₄)alkyl (meth)acrylates, such ashydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropylmethacrylate and hydroxypropyl acrylate; preferably thehydroxy-functional (meth)acrylic monomer is hydroxyethyl methacrylate(HEMA). Suitable amino-functional (meth)acrylic monomers include, forexample, dimethylaminopropyl methacrylamide, dimethylaminopropylacrylamide, dimethylaminoethyl methacrylate, dimethylaminoethylacrylate, dimethyl-aminopropyl methacrylate and dimethylaminopropylacrylate. Suitable thiol-functional (meth)acrylic monomers include, forexample, 2-mercaptopropyl methacrylate.

[0015] When polymer A contains hydroxy-functional (meth)acrylic monomerand the polyfunctional crosslinker agent contains pendant isocyanatefunctional groups, polymer A typically contains, as polymerized units,from 2 to 40%, preferably from 3 to 20%, more preferably from 3 to 15%and most preferably from 5 to 10%, of hydroxy-functional (meth)acrylicmonomer.

[0016] The polymers used as polymer A of the present invention contain,as polymerized units, from 15 to 90%, preferably from 20 to 65% and morepreferably from 25 to 50%, of one or more (C₁-C₂₀)alkyl (meth)acrylateester monomers. Suitable (C₁-C₂₀)alkyl (meth)acrylate ester monomersinclude, for example, methyl acrylate, ethyl acrylate, propyl acrylate,isopropyl acrylate, butyl acrylate, isobutyl acrylate, secondary butylacrylate, tertiary-butyl acrylate, methyl methacrylate, ethylmethacrylate, propyl methacrylate, isopropyl methacrylate, cyclopropyl,methacrylate, butyl methacrylate and isobutyl methacrylate, hexyl andcyclohexyl methacrylate, cyclohexyl acrylate, isobornyl methacrylate,2-ethylhexyl acrylate (EHA), 2-ethylhexyl methacrylate, octyl(meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl(meth)acrylate, dodecyl (meth)acrylate (also known as lauryl(meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate(also known as myristyl (meth)acrylate), pentadecyl (meth)acrylate,hexadecyl (meth)acrylate (also known as cetyl (meth)acrylate),heptadecyl (meth)acrylate, octadecyl (meth)acrylate (also known asstearyl (meth)acrylate), nonadecyl (meth)acrylate, eicosyl(meth)acrylate and combinations thereof. Typically, the (C₁-C₂₀)alkyl(meth)acrylate esters are (C₁-C₈)alkyl (meth)acrylate esters andpreferably (C₁-C₈)alkyl acrylate esters; more preferably, the(C₁-C₂₀)alkyl (meth)acrylate esters are selected from methyl acrylate,ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate; mostpreferably, the acrylate esters are selected from butyl acrylate and2-ethylhexyl acrylate. When the (C₁-C₂₀)alkyl (meth)acrylate ester is a(C₁-C₈)alkyl acrylate ester, the amount of ester in polymer A istypically from 15 to 65%, preferably from 20 to 50% and more preferablyfrom 25 to 45%.

[0017] Polymers used as polymer A of the present invention mayoptionally contain, as polymerized units, from zero up to 70%,preferably from 10 to 60% and more preferably form 20 to 50%, of one ormore vinylaromatic monomers. Suitable vinylaromatic monomers include,for example, styrene, α-methyl styrene and substituted styrenes, such asvinyl toluene, 2-bromostyrene, 4-chlorostyrene, 2-methoxystyrene,4-methoxystyrene, α-cyanostyrene, allyl phenyl ether and allyl tolylether. When present, the vinylaromatic monomer is preferably styrene;levels of vinylaromatic monomer of at least 20% provide an enhancementof gloss characteristics and also enhance the detergent resistance ofdried films of the two-component polymer compositions of the presentinvention.

[0018] Polymers used as polymer A of the present invention mayoptionally contain, as polymerized units, from zero up to 10% andpreferably from zero up to 5%, of one or more other copolymerizablemonomers. Suitable other copolymerizable monomers include, for example,butadiene, acrylonitrile, methacrylonitrile, crotononitrile,α-chloroacrylonitrile, ethyl vinyl ether, isopropyl vinyl ether,isobutyl vinyl ether, butyl vinyl ether, diethylene glycol vinyl ether,decyl vinyl ether, ethylene, methyl vinyl thioether and propyl vinylthioether, esters of vinyl alcohol (such as vinyl formate, vinylacetate, vinyl propionate, vinyl butyrate and vinyl versatate;preferably polymer A is substantially free of vinyl esters of vinylalcohol, that is, from zero to less than 1%, more preferably from zeroto less than 0.5% and most preferably from zero to less than 0.1%, basedon weight of polymer A), poly(alkyleneoxide) di(meth)acrylates,butanediol acrylate, 3-chloro-2-hydroxypropyl acrylate,acetoacetoxyethyl acrylate, acetoacetoxyethyl methacrylate,acetoacetoxypropyl acrylate, acetoacetoxypropyl methacrylate,acetoacetoxybutyl acrylate, acetoacetoxybutyl methacrylate,2,3-di(acetoacetoxy)propyl acrylate, 2,3-di(acetoacetoxy)propylmethacrylate, allyl acetoacetate, amides of ethylenically unsaturated(C₃-C₆)carboxylic acids, amides of ethylenically unsaturated(C₃-C₆)carboxylic acids that are substituted at the nitrogen by one ortwo (C₁-C₄)alkyl groups, acrylamide, methacrylamide and N-methylol(meth)acryl-amide.

[0019] Particularly preferred polymer A compositions useful in thetwo-component coating compositions of the present invention arepolymers, comprising as polymerized monomer units: (a) 16 to 20 percent,based on weight of polymer A, of monoethylenically unsaturated monomercontaining a carboxylic acid functional group; (b) 3 to 15 percent,based on weight of polymer A, of a (meth)acrylic monomer containinghydroxy functional groups; (c) 20 to 50 percent, based on weight ofpolymer A, of vinylaromatic monomer; and (d) 25 to 45 percent, based onweight of polymer A, of one or more (C₁-C₈)alkyl (meth)acrylate estermonomers; where the polymer has a number average molecular weight from200,000 to 1,000,000.

[0020] Polymers used as polymer A in the present invention have numberaverage molecular weights (M_(n)) from greater than 50,000 up to2,000,000, preferably from 100,000 to 1,500,000, more preferably from200,000 to 1,000,000 and most preferably from 400,000 to 800,000. Numberaverage molecular weights for polymer A are based on aqueous phase gelpermeation chromatography (GPC) analysis using known polymer standardsappropriate for the polymer compositions involved. The use of polymer Amaterials having M_(n) less than about 50,000 result in inferiordurability properties of the dried polymer films based on thetwo-component polymer compositions.

[0021] Polymers used as polymer A in the present invention have glasstransition temperatures from zero to 120° C., preferably from 25 to 90°C., more preferably from 40 to 80° C. and most preferably from 50 to 75°C. “Glass transition temperature” or “T_(g)” as used herein, means thetemperature at or above which a glassy polymer will undergo segmentalmotion of the polymer chain. Glass transition temperatures of a polymercan be estimated by the Fox equation (Bulletin of American PhysicsSociety, 1 (3), p 123, 1956) as follows:$\frac{1}{T_{g}} = {\frac{w_{1}}{T_{g{(1)}}} + \frac{w_{2}}{T_{g{(2)}}}}$

[0022] For a copolymer, w₁ and w₂ refer to the weight fraction of thetwo comonomers, and T_(g(1)) and T_(g(2)) refer to the glass transitiontemperatures of the two corresponding homopolymers. For polymerscontaining three or more monomers, additional terms are added(w_(n)/T_(g(n))). The T_(g) of a polymer can also be measured by varioustechniques including, for example, differential scanning calorimetry(DSC).

[0023] Methods for the preparation of the aqueous dispersible polymersused as polymer A in the present invention are well known in the art.Polymer A may be selected from solution, dispersion and emulsionpolymers; preferably polymer A is an emulsion polymer. The practice ofemulsion polymerization is discussed in detail in D. C. Blackley,Emulsion Polymerization (Wiley, 1975). Emulsion polymers useful in thepresent invention may also be formulated using internally plasticizedpolymer emulsions (see U.S. Pat. No. 4,150,005 for further general andspecific details on the preparation of internally plasticized polymeremulsions).

[0024] Conventional emulsion polymerization techniques as describedabove may be used to prepare emulsion polymers suitable for use in thepresent invention. Suitable monomers may be emulsified with anionic ornonionic dispersing agents; for example, 0.5% to 10% based on the weightof total monomers being used. Acidic monomers are water soluble and thusserve as dispersing agents which aid in emulsifying the other monomersused. A polymerization initiator of the free radical type, such asammonium or potassium persulphate, may be used alone or in conjunctionwith an accelerator, such as potassium metabisulphite or sodiumthiosulphate. The initiator and accelerator, commonly referred to ascatalysts, may be used in proportions of 0.1% to 2%, each based on theweight of monomers to be copolymerized. The polymerization temperatureis typically from ambient temperature up to 90° C.

[0025] Examples of emulsifiers suitable for emulsion polymerizationinclude, for example, alkaline metal and ammonium salts of alkyl, aryl,alkaryl and aralkyl sulphonates, sulphates, polyether sulphates, andalkoxylated derivatives of fatty acids, esters, alcohols, amines, amidesand alkylphenols.

[0026] Chain transfer agents, including mercaptans, polymercaptans andpolyhalogen compounds may be used in the polymerization mixture tocontrol molecular weight of the polymer.

[0027] Optionally, low levels of divinyl or polyvinyl monomers, forexample, glycol polyacrylates, allyl methacrylate, and divinylbenzenemay be used to introduce a controlled amount of gel into the emulsionparticles as long as the quality of the polish film formation is notimpaired.

[0028] The polyfunctional crosslinker agents used in the method of thepresent invention contain pendant functional groups selected from one ormore of isocyanate, carbodiimide, aziridinyl and epoxy groups.Typically, the polyfunctional crosslinker agent will be a polymer(designated as polymer B).

[0029] When the functional group of the polyfunctional crosslinker agentis an isocyanate group, the isocyanate group will react withcorresponding reactive functional groups in polymer A based on hydroxyor thiol functionality. When the functional group of the polyfunctionalcrosslinker agent is a carbodiimide group, the carbodiimide group willreact with corresponding reactive functional groups in polymer A basedon carboxyl functionality. When the functional group of thepolyfunctional crosslinker agent is an aziridinyl or epoxy group, thesegroups will react primarily with corresponding reactive functionalgroups in polymer A based on thiol or amino functionality.

[0030] Suitable polyisocyanate, polycarbodiimide, polyyaziridinyl andpolyepoxy crosslinker agents may be based on any aliphatic, aromatic (ormixture thereof) backbone polymer suitably substituted with the desiredpendant functional groups. For example, the backbone polymers may beprepared by conventional vinyl polymerization or condensationpolymerization reactions where the pendant functional groups areincorporated during polymer formation or by post-reaction. Typically,the amount of polyfunctional crosslinker agent (polymer B) used relativeto polymer A in preparing the two-component coating compositions of thepresent invention will be in an amount sufficient to provide from 0.2 to5, preferably from 0.4 to 4 and more preferably from 0.6 to 2,equivalents of isocyanate, carbodiimide, aziridinyl or epoxy functionalgroup, per equivalent of corresponding pendant reactive functional groupin polymer A. Typically, this corresponds to 1 to 90%, preferably from 5to 75% and more preferably from 10 to 50%, of polyfunctional crosslinkeragent (polymer B), based on weight of polymer A.

[0031] When the pendant functional groups of polymer B are carbodiimide,aziridinyl or epoxy groups, the backbone polymer may be based on anysuitable vinyl monomer carrying the corresponding functional group (suchas glycidyl methacrylate) or reactive group that is capable of postreacting to attach the carbodiimide, aziridinyl or epoxy group.

[0032] Alternatively, polyfunctional crosslinker agents based onisocyanate, carbodiimide, aziridinyl or epoxy group functionality may bederived from non-polymeric materials, as long as they are“polyfunctional” in terms of crosslinking efficacy. Suitable polyepoxidecrosslinkers include, for example, (C₄-C₈)diepoxyalkanes anddiepoxyaralkanes such as, 1,2,3,4-diepoxybutane, 1,2,4,5-diepoxypentane,1,2,5,6-diepoxyhexane, 1,2,7,8-diepoxyoctane, 1,4- and1,3-divinyl-benzene diepoxides, (C₆-C₁₅)polyphenol polyglycidyl ethers(such as 4,4′-isopropylidenediphenol diglycidyl ether (also known asbisphenol A diglycidyl ether) and hydroquinone diglycidyl ether),polyglycidyl ethers of (C₂-C₆)alkanepolyols and poly(alkylene glycols)such as, ethylene glycol diglycidyl ether, diethylene glycol diglycidylether, polyethyleneglycol diglycidyl ether, glycerine diglycidyl etherand triglycidyl ether, propylene glycol diglycidyl ether and butanedioldiglycidyl ether, and polyglycidyl ethers of erythritol,trimethylolethane and trimethyolpropane.

[0033] Suitable polyaziridinyl crosslinkers include, for example,polyaziridinyl derivatives of (C₂-C₆)alkanepolyols such as,pentaerythritol-tris[β-(N-aziridinyl)-propionate],trimethylolpropane-tris[β-(N-aziridinyl)propionate],pentaerythritol-bis[β-(N-aziridinyl)propionate] andtrimethylolpropane-bis-[,β-(N-aziridinyl)-propionate].

[0034] When the pendant functional groups of the polyfunctionalcrosslinker agent are isocyanate groups, the crosslinkers are typicallyreferred to as polyisocyanates, such as the water-dispersiblepolyisocyanates and mixtures of polyisocyanates that are commerciallyavailable, for example, from Bayer Corporation (such as Bayhydur™XP-7063, XP-7148, and XP-7165 polyisocyanates) or from MilesCorporation. The polyfunctional crosslinker agent may be any organicpolyisocyanate having free isocyanate groups that are attached toaliphatic, cycloaliphatic, aralkyl or aromatic moieties. Thepolyisocyanates typically have from 2 to 5, preferably from 3 to 4,isocyanate groups per molecule (referred to as [NCO] functionality) with% isocyanate group contents ranging from 10 to 25% and preferably from12 to 20% (by weight). The polyisocyanates are typically based onderivatives of diisocyanates containing one more of isocyanurate,biuret, allophanate, urethane, uretdione and urea groups.Polyisocyanates containing urethane groups (partial urethanization) maybe prepared, for example, by reacting some of the isocyanate groups withmonohydric and polyhydric alcohols, particularly monovalent polyalkyleneoxide polyether alcohols containg from 5 to 10, preferably 6 to 8ethylene oxide units per molecule. U.S. Pat. No. 5,252,696 may beconsulted for further general and specific details regarding suitablewater-dispersible hydrophilically-mocdified polyisocyanates that may beused as the polyfunctional crosslinking agent. Suitable polyisocyanatesinclude, for example, those based on derivatives of1,4-diisocyanatobutane, 1,6-diisocyanatohexane (HDI),1,5-diisocyanato-2,2-di-methylpentane,2,2,4-trimethyl-1,6-diisocyanatohexane,2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane,1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane,1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (isophoronediisocyanate, IPDI), 4,4′-diisocyanatodicyclohexyl-methane,triisocyanates (such as 2,4,4′-triisocyanatodiphenyl ether,4,4′,4″-triisocyanatotriphenylmethane and trimeric1,6-diisocyanatohexane) and dimeric 1,6-diisocyanatohexane. Preferablythe polyisocyanates used as the poly-functional crosslinker agent(polymer B) are based on hydrophilically-modified derivatives of1,6-diisocyanatohexane.

[0035] Additional polyisocyanates, include, for example, those based onaromatic diisocyanates such as 2,4- and 2,6-tolylene diisocyanate,m-phenylene diisocyanate, xylylene diisocyanate, 4,4′-biphenylenediisocyanate, 1,5-naphthylene diisocyanate; preferably thepolyisocyanates used as the polyfunctional crosslinker agent aresubstantially free of aromatic isocyanate derivatives, that is, fromzero to less than 5%, more preferably from zero to less than 1% and mostpreferably from zero to less than 0.5%, based on weight ofpolyfunctional crosslinker agent.

[0036] If insufficient isocyanate functionality is used in thepolyfunctional crosslinker agent in relation to the hydroxyl-functionalpolymer A, that is, less than 0.2 equivalent [NCO] in polyfunctionalcrosslinker agent per equivalent [OH] in polymer A, properties such asdetergent resistance, black heel and scuff mark resistance, marresistance, and responsiveness to floor machine maintenance proceduresof the dried film may be diminished. More specifically, detergentresistance of the polish film is poor when excessive polish filmswelling occurs, decreasing the cohesive strength of the polish film.The mechanical process of detergent scrubbing of a floor polish is thendetrimental to the integrity of the polish film.

[0037] The present invention provides for crosslinking and ambientcuring of aqueous-based film-forming polymers containing carboxyl groupsand reactive functional groups (preferably hydroxyl groups) that arepost-reacted with a polyfunctional crosslinking agent (preferably apolyisocyanate). Polish and coating compositions prepared by the methodof the present invention exhibit improved properties such as detergentresistance, scuff mark resistance, mar resistance and resistance to padinduced scratching from machine maintenance operations. Additionally,aqueous-based polish and coatings compositions prepared by the method ofthe present invention exhibit removability characteristics that areequivalent to conventional metal ion crosslinked polymer systems.

[0038] The coating compositions prepared according to the presentinvention readily dry at temperatures as low as 10° C. and areparticularly suitable for use in the flooring wood and furnitureindustries to provide excellent optical properties (such as surfacegloss, leveling and transparency), durability and easy removability.

[0039] Preparation of aqueous two-component coating compositions by themethod of the present invention involves mixing of the polyfunctionalcrosslinker agent with the water-dilutable poly(meth)acrylate polymer(polymer A) shortly before application (for example, zero to 48 hours,preferably zero to 12 hours). This affords reliable processing of thetwo-component mixture with a relatively long pot life (or processingtime), that is, in a ready-to-use state. It is essential that the bulkof the crosslinking between polymer A and the polyfunctionalcrosslinking agent takes place after application of the aqueous-basedmixture of the two-component polymer composition to a substrate;preferably at least 50% and more preferably at least 75%, of thecrosslinking reaction (based on consumption of polyfunctionalcrosslinker agent) should take place after application of theaqueous-based mixture to a substrate in order to obtain the mostdesirable combination of durability and easy removability of the coatingcomposition.

[0040] Typically, the polymer A component represents 40 to 90%,preferably 50 to 80%, based on the combined weight of polymer A andpolyfunctional crosslinker agent component in the two-component coatingcomposition. Correspondingly, the polyfunctional crosslinker agent(polymer B) component typically represents 10 to 60%, preferably 20 to50%, based on the combined weight of polymer A, and polyfunctionalcrosslinker agent in the two-component coating composition.

[0041] When formulated as a floor polish, the coating compositions ofthe present invention comprise the following components:

[0042] (a) 10 to 100 parts by solids weight of the two-componentwater-insoluble polymer formed by the method of the present invention;

[0043] (b) 0 to 90 parts by solids weight wax (provided as waxemulsion);

[0044] (c) 0 to 90 parts, by solids weight alkali soluble resin (ASR);

[0045] (d) 0.01 to 20 parts (based on weight of polymer solids)surfactant, defoamer, leveling agent, plasticizer and coalescent agent;and

[0046] (e) water, sufficient to provide total polish solids ranging from0.5 to 50%, preferably from 2 to 40% (typically this corresponds to 50to 99% water, based on total weight of the coating composition).

[0047] The amount of component (a) is from 10 to 90%, preferably from 10to 50% and more preferably from 15 to 25%, based on the combined weightof components (a), (b), (c), (d) and (e).

[0048] The amount of component (c), when present, may be up to 100%,preferably from 5 to 50% and more preferably form 3% to 25%, based onthe weight of component (a). Suitable alkali-soluble resins (ASR)contain an acid functional group typically present at greater than 10%of the ASR, have weight average molecular weights below 500,000, andform aqueous solutions when the pH is adjusted between 6 to 10 (see U.S.Pat. No. 3,037,952 for further general and specific details onalkali-soluble resins).

[0049] When component (d) is a coalescent agent, the amount ofcoalescent agent is typically from 0.1 to 15%, preferably 2 to 10%,based on the combined weight of components (a), (b), (c), (d) and (e).Coalescent agents typically aid in the film formation of floor polishesand include, for example, ethylene glycol and propylene glycol ethers(such as diethylene glycol ethyl ether, dipropylene glycol methyl etherand tripropylene glycol methyl ether).

[0050] When component (d) is a leveling agent, the amount of levelingagent is typically from 0.1 to 15%, preferably 1 to 10%, based on thecombined weight of components (a), (b), (c), (d) and (e). Levelingagents typically aid in providing smooth polish films of uniform gloss,and include, for example, tributoxy ethyl phosphate and polyethers(containing no free hydroxyl groups) capped with alkyl groups.

[0051] Conventional surfactants, defoamers, plasticizers and coalescentagents may be used in conventional amounts, depending upon the balanceof performance properties desired by the formulator. Other ingredients,such as perfumes or odor-masking agents, optical brightener, dyes orcolorants, biocides (such as bacteriocides and bacteriostats), may alsobe optionally included by the formulator.

[0052] Optionally, metal ion selected from one or more of polyvalentmetal ion and monovalent alkali metal ion may be used in conjunctionwith polymer A in the method of the present invention. U.S. Pat. Nos.4,517,330 and 5,149,745 may be consulted for further general andspecific details on the preparation of aqueous-based emulsion polymerscrosslinked with polyvalent metal ions. When used in the two-componentcoating compositions prepared by the method of the present invention,the amount of polyvalent metal ion and optionally a basic hydroxide orsalt of an alkali metal, is from 1 to 75% of the equivalents of the acidresidues in polymer A. Preferably, the polyvalent metal is a divalentmetal. For example, a preferred floor polish composition is where thedivalent metal ion content is from 5 to 60%, preferably from 5 to 50%,of the equivalent of the acid residues in polymer A.

[0053] Suitable polyvalent and alkali metal ions useful in the presentinvention are well known in the art. Suitable polyvalent metal ionsinclude, for example zinc, cadmium, nickel, zirconium, strontium,calcium, magnesium and copper; preferably the polyvalent metal ions areselected from zinc, calcium, magnesium and zirconium. Suitablemonovalent alkali metal ions include, for example, lithium, sodium andpotassium ions.

[0054] The optional polyvalent metal ions are typically added to theaqueous medium of the polish composition (pH of 4 to 8) as an aqueousslurry of the oxides, hydroxides, carbonates or bicarbonates of thecorresponding metal ion, for example, CaCO₃, ZnO and Mg(OH)₂. Thepolyvalent metal ions may be incorporated into the two-component coatingcomposition at any stage of its formulation. Similarly, the basic saltof the alkaline metal may be incorporated with the polyvalent metal ionat any stage of formulating the coating composition.

[0055] Some embodiments of the invention are described in detail in thefollowing Examples. All ratios, parts and percentages are expressed byweight unless otherwise specified, and all reagents used are of goodcommercial quality unless otherwise specified. Abbreviations used in theExamples and Tables are listed below with the correspondingdescriptions: BA = butyl acrylate MMA = methyl methacrylate AA = acrylicacid MAA = methacrylic acid HEMA = hydroxyethyl methacrylate ST =styrene [COOH] = carboxyl concentration [equivalents] [NCN] =carbodiimide concentration [equivalents] [NCO] = isocyanateconcentration [equivalents] [OH] = hydroxyl or hydoxy groupconcentration [equivalents]

[0056] Test Methods

[0057] Mar Resistance: This test is based on striking the coating at ashallow angle with a hard object; in the examples provided, the objectwas the fingernail of the individual performing the test. This testgives an indication of how the coating will resist marring, which leadsto gloss reduction of the coating.

[0058] After the coating is applied to the substrate and allowed tocure, the coated substrate is placed on a solid surface such as a tabletop and struck with the operator's fingernail. The operator's fingernailis kept parallel to the coated surface and the impact angle is greaterthan 45° from the normal of the surface, to increase the likelihood ofmarking the coating.

[0059] When comparing coatings, it was important that the same operatorperform the test. This test was designed to distinguish relativedifferences.

[0060] We used the following rating system: Rating Appearance 1 -Excellent (Exc) No perceptible marks 3 - Good Marks which appear as thinscratches (<1 mm) 5 - Poor Marks which are wide (>1 mm)

[0061] Black Heel Mark and Scuff Resistance: The method for determiningblack heel and scuff resistance described in Chemical SpecialtyManufacturers Association Bulletin No. 9-73 was utilized, except thatcommercially available rubber shoe heels were used in place of therecommended 5.08 cm (2 inch) rubber cubes. Furthermore, instead ofsubjectively rating the coated substrate, the percentage of the coatedsubstrate area covered by black heel and scuff marks was determined;this was conveniently performed with transparent graph paper. A blackheel mark is an actual deposition of rubber onto or into the coating,whereas a scuff mark results from physical displacement of the coatingwhich appears as an area of reduced gloss. Scuff and black heel markscan occur simultaneously at the point where the heel impacts thesubstrate, that is, upon removal of a black heel mark, a scuff may bepresent.

[0062] Gloss: The method for determining the gloss performance of polishcompositions is described in “Annual Book of ASTM Standards,” Section15, Volume 15.04, Test Procedure ASTM D 1455 (2000). A Gardner BykMicro-Tri-Gloss meter, catalog number 4520, was used to record 60° and20° gloss.

[0063] Recoatability: The method for determining the recoatability ofwater-based emulsion floor polishes is described in “Annual Book of ASTMStandards,” Section 15, Volume 15.04, Test Procedure ASTM D 3153 (2000).

[0064] Water Resistance: The method for determining the water resistanceof polish compositions is described in “Annual Book of ASTM Standards,”Section 15, Volume 15.04, Test Procedure D 1793 (2000), and thefollowing scale was used to rate the water resistance of the coatingcompositions: Rating Appearance Excellent (Exc) No water mark orperceptible damage to coating Very Good (VG) Faint water outline GoodSlight degree of film whitening Fair Film whitening with some blistersand lifting Poor Complete film failure with gross whitening/loss ofadhesion

[0065] Detergent Resistance: The method for determining detergentresistance is described in “Annual Book of ASTM Standards,” Section 15,Volume 15.04, Test Procedure ASTM D 3207 (2000), except that a 1/20dilution of Forward™ (S. C. Johnson and Sons, Inc., Racine, Wis.) inwater was used as test detergent solution and a 1000 gram weight wasadded to the brush assembly.

[0066] Removability: The method for determining polish removability isdescribed in “Annual Book of ASTM Standards,” Section 15, Volume 15.04,Test Procedure ASTM D 1792 (2000), except a 1000 gram weight was addedto the brush assembly.

[0067] Film Formation: A draw-down using 0.4 ml of the coatingcomposition was applied by means of a 2 inch (5.08 cm) wide bladeapplicator (as specified in ASTM D 1436 (2000)), having a clearance of0.008 inches (0.02 cm), to a length of 4 inches (10.16 cm) on a vinylcomposition tile. Immediately after application of the polish, the tilewas placed on a level surface in a refrigerator at 10° C. The dried filmwas rated as follows: Rating Appearance Excellent (Exc) No crazing (nofine cracks in surface) Very Good (VG) Slight edge crazing Good Definiteedge crazing Fair Definite edge crazing with very slight center crazingPoor Complete edge and center crazing

[0068] Coating Application: The method for applying the floor polishcoating to substrates for testing purposes is described in “Annual Bookof ASTM Standards,” Section 15, Volume 15.04, Test Procedure ASTM D 1436(2000), Test Method B.

[0069] Floor Tests for Leveling Performance

[0070] The floor test areas were stripped of residual polish andrepolished in the typical janitorial procedure as follows:

[0071] The floors were dust mopped to remove loose dirt, a 1:1 aqueoussolution of commercial stripper solution (“SSS Easy Strip” StandardizedSanitation Systems, Inc., Burlington, Mass.) was applied by string mopat a rate of about 1,000 square feet/gallon (25 m²/L); after a fiveminute soak period the floors were scrubbed with a sixteen inch (41 cm)black stripping floor pad (“Scotch Brite” Slim Line Floor Pad, 3MCompany, St. Paul, Minn.) on a 175 rpm floor machine (Howell ElectricMotors, Plainfield, N.J. Model 88400-026); the stripped floors werethoroughly rinsed twice by damp mopping with clear water, and allowed todry. The stripped floors were divided into 20 square foot (2 m²)sections perpendicular to the normal direction of floor traffic flow. Toeach of the sections four coats of polish to be tested were applied,with a SSS Finish Wide Band, Small cotton/rayon string mop No. 37627, ata rate of about 50 m²/L (2,000 square feet/gallon). Immediately afterthe spreading of each coat was completed, an “X” mark was placed in thewet polish surface by drawing the string mop diagonally from corner tocorner of the test area. Each coat was allowed to dry for one hourbefore the next coat was applied.

[0072] Coatings were applied (4 coats) to floors composed of homogenousvinyl and vinyl composition tiles, and cured at ambient conditions.After the coatings had dried they were examined visually to determinethe extent of the disappearance of the “X” compared to a comparativepolish. This test was designed to distinguish relative differences inthe disappearance of the “X” mark. Leveling was rated on the followingscale: Rating Appearance (relative to disappearance of “X” mark) 5 muchbetter than the comparative 4 better than the comparative 3 equivalentto the comparative 2 worse than the comparative 1 much worse than thecomparative

[0073] Floor Wear Tests for Resistance Properties and MachineMaintenance Responsiveness

[0074] The same procedure outlined for determining the levelingperformance of polishes described in the test method section “FloorTests for Leveling Performance” was used for the preparation of thefloor substrate and polish application. After the coatings had cured atambient conditions for a specific time, the floors were opened topedestrian traffic. The floor test areas were exposed to foot traffic aswell as wheeled traffic from maintenance carts, sample trays, etc. Thevisual gloss as well as scuffing and scratching before and after asufficient exposure to traffic were measured. Machine burnishingmaintenance was performed on the test floors in the typical janitorialfashion as described below.

[0075] The floors were dust mopped to remove loose dirt; the floors wereburnished with an eighteen inch UHS Tan Buffer Pad (“Scotch Brite” UltraHigh Speed Tan Buffer Pad, 3M Company, St. Paul, Minn.) on a 2000 rpmpropane floor burnishing machine (Pioneer “2100” Superbuffer™ Model#SB2100, Pioneer/Eclipse Corporation, Sparta, N.C.). The test floorswere exposed to two passes of the burnishing machine, five times perweek, for a four week period. The visual gloss after burnishing orburnish response as well as the pad scratch resistance of the testfinishes were measured on a weekly basis.

[0076] When comparing coatings for pad induced scratching from machineburnishing operations, it is important that the same operator performthe test and evaluate the response of the coating. This test is designedto distinguish relative differences.

[0077] We used the following rating system: Rating Appearance 1 - Nil -No perceptible marks 3 - Slight - Marks which appear as thin (<1 mm)circular scratches 5 - Moderate - Marks which are wide (>1 mm) circularscratches

[0078] Floor Tests for Detergent Resistance and Removability Testing

[0079] Floors were prepared and polishes applied as described in thesection for “Floor Tests for Leveling Performance;” testing wasperformed on the same floors mentioned in the “Floor Wear Tests forResistance Properties and Machine Maintenance Responsiveness” section.For detergent resistance testing, the floors were dust mopped to removeloose dirt, a ⅓ dilution of Forward DC (S. C. Johnson & Son, Inc.,Racine, Wis.) in water was charged to a floor scrubbing machine equippedwith a sixteen inch (41 cm) blue scrubbing pad (“Scotch Brite” Slim LineFloor Pad, 3M Company, St. Paul, Minn.). The scrubbing operationinvolved two passes with the machine over the test floors. The samemachine used to deposit the detergent and scrub the floors was also usedto remove the detergent solution and dry the floor. The polish coatingswere evaluated for film damage/removal and haze. Additionally, 20° glosswas measured to determine gloss differences before and after scrubbing.

[0080] Evaluation of the removability of the polish coating from thefloor tests was performed in the identical manner outlined for preparingthe floor for testing, after 24 weeks of exposure to pedestrian trafficand machine burnishing operations. The polish coatings were evaluatedfor film removal and ease of removal.

[0081] Unless otherwise indicated in these examples, the followingterms, symbols and/or abbreviations should be understood to have themeanings shown below. The following abbreviations and terms are used asindicators of position on scales of ratings used in reporting thedetergent resistance, removability, black heel mark resistance, scuffmark resistance and pad swirling resistance from machine maintenancetests reported in the Examples, where “Very Poor” is the lowest ratingand “Excellent” the highest rating. For example, a 10-point scale wouldinclude the following designations: VP = Very Poor P = Poor P-F = Poorto Fair F = Fair F-G = Fair to Good G = Good G-VG = Good to Very Good VG= Very Good VG-Exc = Very Good to Excellent Exc = Excellent

[0082] Formulation of a Floor Polish Composition for Testing

[0083] In order to evaluate the performance of polymer A candidates(polymers containing an acidic functional group) for use in polishvehicles, the polymers were added into a standard floor polishformulation. The formulation presented below is representative ofconventional floor polish formulations known to those skilled in theart. The ingredients used and their proportions and manner of additionare representative of those commonly practiced with conventionaltechnology emulsion polymers.

[0084] Floor polish formulations based on using Part 1 alone representsingle-component (single-stage or “1-pot”) formulations. Floor polishformulations based on using Part 1 in conjunction with Part 2 arerepresentative of the two-component (two-stage or “2-pot”) compositionsof the present invention.

[0085] The floor polish formulation was prepared by adding Part 1 to anappropriate container based on quantity needed for specific test. Forexample, 100 g of Part 1 was charged to a 113-ml (4-ounce) glass jar,which served as a mixing vessel. When two-component compositions weretested, Part 2 (polyfunctional crosslinking agent, polyisocyanatedispersion) was then added to the mixing vessel in an amount sufficientto react with the hydroxy functionality of polymer A in the Part 1component. The specific amount of polyfunctional crosslinking agent usedvaried and is specified by the [NCO]:[OH] stoichiometric ratio in theexamples below. The resultant mixture was then stirred [for 5 minutes atambient temperature.

[0086] Part 1 (contains polymer A): (see order of addition below) AmountMaterial Function (parts by weight) Water diluent 50.7 FC-120 (1%)¹wetting agent 1.00 Kathon ™ CG/ICP biocide 0.03 (1.5%)² SE-21³ defoamer0.02 Diethylene Glycol coalescent 4.5 Ethyl Ether Tributoxy Ethylleveling agent 1.0 Phosphate Polymer A (as 38% vehicle 30.6 solidsemulsion) AC-316N (30%)⁴ Aqueous polyethylene 6.9 wax emulsion

[0087] Part 2 (contains polyfunctional crosslinker agent):Water-dispersible polyisocyanate based on derivatives of1,6-diisocyanatohexane (HDI) available as Bayhydur™ XP-7148polyisocyanate from Bayer Corporation, Pittsburgh, Pa.: 100% activeingredient, 14.4% [NCO], 3.1 average [NCO] functionality, 292g/equivalent [NCO].

[0088] In a preferred embodiment, Part 2, containing the crosslinkeragent, will also contain the leveling agent, that is, the leveling agentis not included in Part is 1, but is instead added as a component ofPart 2. In this case, the presence of the leveling agent in Part 2improves the fluidity and viscosity of the Part 2 component and improvesthe mixing of Part 1 and Part 2 components. In addition, this mode ofaddition minimizes any gel formation that may occur during the mixing ofParts 1 and 2.

[0089] We have found that when the leveling agent is included in Part 2instead of in Part 1, dual chambered storage containers can be used withPart 1 and Part 2 (containing tributoxy ethyl phosphate) without any gelformation when the two components are ultimately mixed together.

[0090] Panel Testing of Floor Polish Compositions

[0091] To vinyl composition panels, 2 coats of polish based on differentPart 1/Part 2 combinations were applied (see description in the sectionfor “Coating Application”) with about one hour between coats. After thefinal coat, the coated panels were allowed to cure at 25° C. for 24hours before testing. This format was used to evaluate mar, black heelmark, scuff and detergent resistance as well as polish filmremovability.

[0092] Experimental Test Result

[0093] Testing of Examples 1-3 demonstrates the improvement inperformance properties of polish films using the two-component polymercompositions of the present invention based on a conventionalaqueous-based emulsion polymer as polymer A (see U.S. Pat. No. 5,149,745for further general and specific details on the preparation of theseaqueous-based emulsion polymers). The polymer A (40 BA/6 MMA/38 ST/5HEMA/11 MAA) emulsion further contained 5 equivalent % Zn⁺⁺ (added asZnO, based on equivalents of MAA) and 2.2% K⁺(added as KOH, based onemulsion solids), with a final solids content of 38% by weight and afinal pH of 7.5 (this solids level and pH adjustment was used throughoutregarding polymer A emulsions, unless indicated otherwise).

Example 1 Comparative

[0094] Example 1 was formulated as a test composition as described inPart 1 (see section on “Formulation of a Floor Polish Composition forTesting”), except that 30.9 grams of water was used instead of 50.7 g,to provide a final polish formulation with 20% solids. Polymer Aemulsion had an [OH] equivalent weight of 6848, based on the HEMAcontent of polymer A.

EXAMPLE 2

[0095] Example 2 was formulated as a test composition by combining the94.8 g of Part 1 (containing polymer A) with 5.2 g of Part 2(polyfunctional crosslinking agent) to provide a final polishformulation with 20% solids with an [NCO]:[OH] stoichiometric ratio of4:1.

[0096] Table 1 summarizes the performance results of Examples 1 and 2,showing that the two-component coating composition provided enhanceddurability characteristics (mar, black heel mark, scuff and detergentresistance) while also providing excellent polish film removability Bycontrast, the single-component coating composition, while having goodremovability, had much poorer durability (mar and scuff) properties.TABLE 1 Ex 1* Ex 2 Mar 5   1   Black Heel Mark Resistance (% Coverage)3.5 3.5 Scuff Mark Resistance (% Coverage) 2.9 2.0 Gloss 60°/20° 70/3875/43 Recoatability Good Good Water Resistance VG-Excellent ExcellentDetergent Resistance Good Excellent Removability Excellent ExcellentFilm Formation Excellent Excellent

EXAMPLE 3 Comparative

[0097] Example 3 was formulated as a test composition as described inPart 1, except that 30.9 g of water was added instead of 50.7 g, toprovide a final polish formulation with 20% solids. Polymer A emulsionused a two-component emulsion polymer having an overall composition of30 BA/10.5 MMA/5 HEMA/4.5 MAA//40 ST/6 MMA/5 AA and had an [OH]equivalent weight of 6848, based on the HEMA content of polymer A (seeU.S. Pat. No. 4,150,005 for further general and specific details on thepreparation of these aqueous-based emulsion polymers). The polymeremulsion was adjusted to a pH 7.5 with ]KOH and had a final solidscontent of 38%.

EXAMPLE 4 Comparative

[0098] Example 4 was formulated as described in Example 3, except thatpolymer A emulsion further contained 5 equivalent % Zn⁺⁺ (added as ZnO,see U.S. Pat. No. 5,149,745 for further general and specific details onthe preparation of these Zn-containing emulsion polymers).

EXAMPLE 5

[0099] Example 5 was formulated as described in Example 4, except that50.7 g of water was added instead of 30.9 g, and the resulting Part 1(containing polymer A) portion was combined with 5.2 g of Part 2(polyfunctional crosslinking agent) to provide a final polishformulation with 20% solids with an [NCO]:[OH] stoichiometric ratio of4:1.

EXAMPLE 6

[0100] Example 6 was formulated as described in Example 3, except that50.7 g of water was added instead of 30.9 g, and the resulting Part 1(containing polymer A) portion was combined with 5.2 g of Part 2(polyfunctional crosslinking agent) to provide a final polishformulation with 20% solids with an [NCO]:[OH] stoichiometric ratio of4:1.

EXAMPLE 7 Comparative

[0101] Example 7 was formulated as a test composition as described inPart 1, except that 30.9 g of water was added instead of 50.7 g, toprovide a final polish formulation with 20% solids. Polymer A emulsionused a two-component emulsion polymer having an overall composition of30 BA/10.5 MMA/5 HEMA/2.5 MAA//7.3 BA/4 ST/40.2 MMA/ 0.5 MAA and had an[OH] equivalent weight of 6848, based on the HEMA content of polymer A(see U.S. Pat. No. 4,150,005 for further general and specific details onthe preparation of these aqueous-based emulsion polymers).

EXAMPLE 8 Comparative

[0102] Example 8 was formulated as described in Example 7, except that50.7 g of water was added instead of 30.9 g, and the resulting Part 1(containing polymer A) portion was combined with 5.2 g of Part 2(polyfunctional crosslinking agent) to provide a final polishformulation with 20% solids with an [NCO]:[OH] stoichiometric ratio of4:1.

[0103] Data in Table 2 show that the crosslinking occurring duringpolish film formation with the addition of the polyfunctionalcrosslinking agent (polyisocyanate) in the compositions of Examples 5, 6and 8 provides dried polish films with improved mar, black heel andscuff mark resistance compared to the single-component polishcompositions. Although the composition of Example 8 showed improved mar,black heel and scuff mark resistance compared to the single-componentpolish compositions (Examples 3, 4 and 7), it was still deficient inremovability properties relative to Examples 5 and 6, which showed thecombined improvement of durability and removability. TABLE 2 Ex 3* Ex 4*Ex 5 Ex 6 Ex 7* Ex 8* % Acid Monomer 9.5 9.5 9.5 9.5 3 3 in Polymer AMar 5 3 1 1 5 1 BHMR 5.7 4.1 3.6 3.5 5.9 3.5 Scuff Mark 6.5 4.5 3.9 4.06.2 4.1 Gloss 60°/20° 70/43 78/45 78/50 70/42 72/42 75/45 RecoatabilityGood VG VG Good Good Good Water Resistance Fair VG-Exc Exc Exc Good ExcDetergent Poor Good Exc Exc Good Exc Resistance Removability Exc Exc ExcGood Poor Poor Film Formation Exc Exc Exc Exc Exc Exc

EXAMPLE 9 Comparative

[0104] Example 9 was formulated as a test composition as described inPart 1, except that 30.9 g of water was added instead of 50.7 g, toprovide a final polish formulation with 20% solids. Polymer A emulsionused a polymer having a composition of 30 BA/9 MMA/40 ST/5 HEMA/16 MAAand had an [OH] equivalent weight of 6848, based on the HEMA content ofpolymer A (see EP 789,063 for further general and specific details onthe preparation of these aqueous-based emulsion polymers). The polymeremulsion containing Polymer A further contained 20 equivalent % Mg⁺⁺(added as Mg(OH)₂) and 2.2% K⁺ (added as KOH, based on emulsion solids),with a final solids content of 38%.

EXAMPLE 10

[0105] Example 10 was formulated as described in Example 9, except that50.7 g of water was added instead of 30.9 g, and the resulting Part 1(containing polymer A) portion was combined with 5.2 g of Part 2(polyfunctional crosslinking agent) to provide a final polishformulation with 20% solids with an [NCO]:[OH] stoichiometric ratio of4:1.

EXAMPLE 11

[0106] Example 11 was formulated as a test composition as described inPart 1, except that 30.9 g of water was added instead of 50.7 g, toprovide a final polish formulation with 20% solids. Polymer A emulsionused a polymer having a composition of 40 BA/1 MMA/38 ST/5 HEMA/16 MAAand had an [OH] equivalent weight of 6848, based on the HEMA content ofpolymer A (see EP 789,063 for further general and specific details onthe preparation of these aqueous-based emulsion polymers). The polymeremulsion containing Polymer A further contained 6.6 equivalent % Mg⁺⁺(added as Mg(OH)₂) and 2.2% K⁺ (added as KOH, based on emulsion solids),with a pH of 7.35 and a final solids content of 38%. The resulting Part1 (containing polymer A) portion was combined with 4.48 g of Part 2(polyfunctional crosslinking agent) to provide a final polishformulation with 20% solids with an [NCO]:[OH] stoichiometric ratio of3.4:1.

[0107] Data in Table 3 (Examples 9-11) show that the crosslinkingoccurring during polish film formation with the addition ofpolyfunctional crosslinking agent (polyisocyanate) in the compositionsof Examples 10-11 (using polymer containing 16% acid monomerfunctionality) provides dried polish films with improved mar, blackheel, scuff mark, detergent and water resistance compared to thesingle-component polish composition, while maintaining the same highdegree of removability observed for the single-component polishcomposition. TABLE 3 Ex 9* Ex 10 Ex 11 Mar 5   1   1   Black Heel MarkResistance 5.0 3.7 4.0 (% Coverage) Scuff Mark Resistance (% Coverage)5.5 1.5 4.5 Gloss 60°/20° 75/40 75/40 78/42 Recoatability Good Good GoodWater Resistance VG-Exc Excellent Excellent Detergent Resistance GoodExcellent Excellent Removability Excellent Excellent Excellent FilmFormation Excellent Excellent Excellent

EXAMPLE 12 Comparative

[0108] Example 12 was formulated as a test composition as described inPart 1, except that 30.9 g of water was added instead of 50.7 g, toprovide a final polish formulation with 20% solids. Polymer A emulsionused a polymer having a composition of 27 BA/9 MMA/38 ST/10 HEMA/16 MAAand had an [OH] equivalent weight of 3424, based on the HEMA content ofpolymer A (see EP 789,063 for further general and specific details onthe preparation of these aqueous-based emulsion polymers). The polymeremulsion containing Polymer A further contained 20 equivalent % Mg⁺⁺(added as Mg(OH)₂) and 2.2% K⁺ (added as KOH, based on emulsion solids),with a final solids content of 38%.

EXAMPLE 13

[0109] Example 13 was formulated as described in Example 12, except that50.7 g of water was added instead of 30.9 g, and the resulting Part 1(containing polymer A) portion was combined with 5.2 g of Part 2(polyfunctional crosslinking agent) to provide a final polishformulation with 20% solids with an [NCO]:[OH] stoichiometric ratio of2:1.

EXAMPLE 14

[0110] Example 14 was formulated as a test composition as described inPart 1, except that 30.9 g of water was added instead of 50.7 g, toprovide a final polish formulation with 20% solids. Polymer A emulsionused a polymer having a composition of 24 BA/50 ST/10 HEMA/16 MAA andhad an [OH] equivalent weight of 3424, based on the HEMA content ofpolymer A. The polymer emulsion containing Polymer A further contained6.6 equivalent % Mg⁺⁺ (added as Mg(OH)₂) and 2.2% K⁺ (added as KOH,based on emulsion solids), with a final solids content of 38%. Theresulting Part 1 (containing polymer A) portion was combined with 8.6 gof Part 2 (polyfunctional crosslinking agent) to provide a final polishformulation with 20% solids with an [NCO]:[OH] stoichiometric ratio of3.3:1.

EXAMPLE 14A

[0111] Example 14A was formulated as a test composition as described inExample 14, except that the leveling agent was not present in Part 1,and was instead included in Part 2. The resulting Part 1 (containingpolymer A) portion was combined with 6.2 g of Part 2 (5.2 g ofpolyfunctional crosslinking agent plus 1 g of tributoxy ethyl phosphate)to provide a final polish formulation with 20% solids with an [NCO]:[OH]stoichiometric ratio of 2:1.

[0112] Table 4 summarizes the performance of Examples 12-14A based on“floor wear” testing (see “Floor Tests for Leveling Performance” and“Floor Wear Tests for Resistance Properties and Machine MaintenanceResponsiveness” previously described). TABLE 4 Film Gloss after Removal/Scuff Machine Pad Detergent Ease of Ex # Leveling Mark BurnishingScratch Resist Removal  5* Good Good VG-Exc 3 VG Exc/Exc  12* Good FairVG-Exc 3 Good Exc/Exc 13 Good Exc VG-Exc 1 Exc Exc/Good 14 Good ExcVG-Exc 1 Exc Exc/Good  14A Good Exc VG-Exc 1 Exc Exc/Good

[0113] The crosslinking occurring during polish film formation with theaddition of polyfunctional crosslinking agent in Examples 13-14 providesthe polish film with improved resistance to pad scratching from floormachine burnishing operations compared to non-polyisocyanate containingpolish and the comparative zinc-containing (or magnesium-containing)single-component polish, Example 5 (Example 12). Examples 13-14 alsoprovided much better scuff mark resistance and detergent resistance thanthe single-component polish composition, yet still maintaining filmremovability comparable to the single-component polish.

EXAMPLE 15

[0114] Example 15 was formulated as a test composition as described inPart 1A below. Polymer A emulsion used a polymer having a composition of24 BA/50 ST/10 HEMA/16 MAA. The polymer emulsion containing Polymer Afurther contained 6.6 equivalent % Mg⁺⁺ (added as Mg(OH)₂) and 2.2% K⁺(added as KOH, based on emulsion solids), with a pH of 7.5 and a finalsolids content of 38%. The resulting Part 1A (containing polymer A)portion was combined with 9.5 g of Part 2A (polyfunctional crosslinkingagent based on carbodiimide (NCN) functionality, see below) to provide afinal polish formulation with a [NCN]:[COOH] stoichiometric ratio of0.5:1.

[0115] Part 1A (contains polymer A): (see order of addition below)Amount Material Function (parts by weight) Water diluent 55.6 FC-120(25%)¹ wetting agent 0.02 SE-21² defoamer 0.02 Diethylene Glycolcoalescent 4.72 Ethyl Ether Tributoxy Ethyl leveling aid 2.0 PhosphatePolymer A (as 38% vehicle 32.4 solids emulsion) AC-316N (30%)³ Aqueouspolyethylene 7.2 wax emulsion

[0116] Part 2A (contains polyfunctional crosslinking agent):Water-dispersible multifunctional carbodiimide available as UCARLNK™XL-29SE crosslinker from Union Carbide Corporation, Danbury, Conn.: 50%active ingredient (in propylene glycol monomethyl ether acetatesolvent), 410 g/equivalent [NCN].

[0117] Table 5 shows the improvement (Example 15: two-componentcomposition) in durability (mar, black heel mark and scuff markresistance) while maintaining removability relative to asingle-component polish composition (represented by Example 1), when thepolyfunctional crosslinking agent is based on carbodiimidefunctionality. TABLE 5 Ex 15 Ex 1* Mar 1 5 Black Heel Mark Resistance (%Coverage) 2.0 3.5 Scuff Mark Resistance (% Coverage) 1.5 2.9 Gloss 60°/20° 74/36 70/38 Recoatability Good Good Water Resistance Excellent VG -Excellent Detergent Resistance Excellent Good Removability ExcellentExcellent Film Formation Excellent Excellent

We claim:
 1. A method for preparing a coating composition comprising: (A) forming an aqueous-based mixture by combining: (i) a first polymer comprising, as polymerized monomer units: (a) 5 to 50 percent, based on weight of the first polymer, of a monoethylenically unsaturated monomer containing an acidic functional group selected from one or more of carboxylic, sulfonic and phosphonic groups; (b) zero up to 60 percent, based on weight of the first polymer, of a (meth)acrylic monomer containing one or more pendant reactive functional groups selected from hydroxy, thiol, and amino groups; (c) zero up to 70 percent, based on weight of the first polymer, of one or more vinylaromatic monomers; (d) 15 to 90 percent, based on weight of the first polymer, of one or more (C₁-C₂₀)alkyl (meth)acrylate ester monomers; and (e) zero up to 10 percent, based on weight of the first polymer, of one or more other copolymerizable monomers; and (ii) a polyfunctional crosslinker agent comprising pendant functional groups selected from one or more of isocyanate, carbodiimide, aziridinyl and epoxy groups; wherein, the first polymer has a number average molecular weight from greater than 50,000 up to 2,000,000; and the polyfunctional crosslinker agent is used in an amount sufficient to provide from 0.2 to 5 equivalents of pendant functional group per equivalent of corresponding pendant reactive functional group in the first polymer; and (B) applying the aqueous-based mixture to a substrate.
 2. The process of claim 1 wherein the first polymer comprises, as polymerized monomer units, 9 to 40 percent of the monoethylenically unsaturated monomer containing an acidic functional group, wherein the acidic functional group is a carboxyl group.
 3. The process of claim 1 wherein the first polymer comprises, as polymerized units, from 2 to 40 percent of the (meth)acrylic monomer which is a hydroxy-functional monomer selected from one or more of hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate and hydroxypropyl acrylate.
 4. The process of claim 1 wherein the first polymer comprises, as polymerized units, from 2 to 40 percent of the (meth)acrylic monomer which is a amino-functional monomer selected from one or more of dimethylaminopropyl methacrylamide, dimethylaminopropyl acrylamide, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminopropyl methacrylate and dimethylaminopropyl acrylate.
 5. The process of claim 1 wherein the first polymer further comprises 1 to 75 percent, based on equivalents of carboxylic acid groups, of polyvalent metal ion.
 6. The process of claim 1 further comprising adding to the aqueous-based mixture of step (A), part (ii), from 0.1 to 15 percent, based on weight of the aqueous-based mixture, of leveling agent.
 7. The process of claim 1 wherein the pendant functional group of the polyfunctional crosslinker agent is an isocyanate group in an amount sufficient to provide from 0.2 to 5 equivalents of isocyanate group per equivalent of hydroxy or thiol functional group in the first polymer.
 8. The process of claim 1 wherein the pendant functional group of the polyfunctional crosslinker agent is a carbodiimide group in an amount sufficient to provide from 0.2 to 5 equivalents of carbodiimide group per equivalent of carboxylic acid functional group in the first polymer.
 9. The process of claim 1 wherein the pendant functional group of the polyfunctional crosslinker agent is an epoxy or aziridinyl group in an amount sufficient to provide from 0.2 to 5 equivalent of epoxy or aziridinyl group per equivalent of amino or thiol functional group in the first polymer.
 10. An aqueous coating composition comprising: (1) a first polymer comprising, as polymerized monomer units: (a) 5 to 50 percent, based on weight of the first polymer, of a monoethylenically unsaturated monomer containing an acidic functional group selected from one or more of carboxylic, sulfonic and phosphonic groups; and (b) zero up to 60 percent, based on weight of the first polymer, of a (meth)acrylic monomer containing one or more pendant reactive functional groups selected from hydroxy, thiol, and amino groups; and (c) zero up to 70 percent, based on weight of the first polymer, of one or more vinylaromatic monomers; and (d) 15 to 90 percent, based on weight of the first polymer, of one or more (C₁-C₂₀)alkyl (meth)acrylate ester monomers; and (e) zero up to 10 percent, based on weight of the first polymer, of one or more other copolymerizable monomers; (2) a polyfunctional crosslinker agent comprising pendant functional groups selected from one or more of isocyanate, carbodiimide, aziridinyl and epoxy groups; (3) 0.1 to 15 percent, based on weight of the aqueous coating composition, of coalescing agent; (4) zero up to 10 percent, based on weight of the aqueous coating composition, of additives selected from one or more of waxes, surfactants, defoamers, leveling agents, alkali-soluble resins and plasticizers; and (5) 50 to 99 percent, based on weight of the aqueous coating composition, of water; wherein: the first polymer has a number average molecular weight from greater than 50,000 up to 2,000,000; the polyfunctional crosslinker agent is used in an amount sufficient to provide from 0.2 to 5 equivalents of pendant functional group per equivalent of corresponding pendant reactive functional group in the first polymer; the combined amount of (1) and (2) is from 10 to 90 percent, based on weight of the aqueous coating composition; and the sum of (1), (2), (3), (4) and (5) percents add up to 100 percent. 